You score bonus points for continuing your metaphorical or using previous parts of your story as an allusion.

For example, I had written:

I just can't understand Ahmad and Alain. I imagine an astronomer looking at radio waves from outer space, and suddenly seeing a pattern that shouldn't be there, and not knowing why it's there or what it means.

Later I wrote:

Boy #3. The confused astronomer notes, with astonishment, that the pattern from outer space is still repeating.

And later:

I stare at the flyer, trying to comprehend what just happened. It's like the astronomer found the same pattern written in Brail on a cereal box.

One of my favorite continuations, which I noticed only because I was studying it, was this. A lawyer is talking to his client who is about to enter prison, and he describes the client as being damned. Then, more than a page later, when the conversation is over and the client is entering prison, he describes the client as about to enter hell. So the author was true to his metaphor. (Hart, King of Lies, near the start).

This is an elaborate metaphorical:

She glanced into the big purse as if there were something inside it that she was hoping she wouldn't have to show me, as if the purse were somehow a point of no return, and if she opened it and let out whatever was inside, she would never be able to close it again or return the elements of her life to a comfortable or of familiar level. Pandora's purse. (Free Fall, Crais, pages 3-4)

And moments later we read:

"But if you don't tell me about him, or what you think he's up to, I can't help you. Do you see that?"
She nodded and held the purse tighter.
(page 4)

The continuation can occur quickly:

My hand is the Tyrannosaur in the room; they're trying to believe it's Bambi.

These are two lexaphors that fit together.

All else had been pared away by the razor-sharp reality of his [prison] sentence. (The King of Lies)

As opposed to two lexaphors clashing:

It sent a wave of nausea loose in Del's stomach. (Split Second, Kava, page 15 paperback)

Wave and loose are acceptable lexaphors, but they don't work together – a wave can't be penned up and then set loose.